The White House on Monday said it “strongly opposes” the amendment attached last month to the House spending bill that includes the D.C. budget. The amendment, offered by Rep. Andy Harris (R-Md.), would bar the District government from spending any money on provisions that weaken its drug laws.

The Harris Amendment, the Obama administration says, “undermines the principles of States’ rights and of District home rule” — which, setting aside the fact that the District is not a state, explicitly suggests that the White House believes marijuana policy should be left to individual jurisdictions.

The Drug Policy Alliance, a national advocacy group, called that a “groundbreaking policy position” in a news release. “It is great to see the White House accepting that a majority of Americans want marijuana law reform and defending the right of D.C. and states to set their own marijuana policy,” said Bill Piper, the group’s director of national affairs. “The tide has clearly shifted against the failed war on drugs and it’s only a matter of time before federal law is changed.”

The administration statement is not a total surprise: It is in keeping, for instance, with the Justice Department’s express hands-off policy toward local marijuana liberalization efforts across the country, and Obama has made comments tolerating the legalization laws in Colorado and Washington as “experiments.” But framing the debate as a matter of “states’ rights” could have an effect on the national debate over cannabis laws.

What may be of greater interest on the local level is that the White House statement also appears to endorse concerns that the Harris Amendment may have inadvertently legalized marijuana, saying the budget rider “poses legal challenges to the Metropolitan Police Department’s enforcement of all marijuana laws currently in force in the District.”

The D.C. decriminalization law is set to pass through a congressional review period and take effect later this week. Should the Harris Amendment subsequently become law, police could be barred from enforcing the new law, which makes small-time marijuana possession punishable by a $25 civil citation, without having a local criminal statute left to enforce. City lawyers were tasked with examining the possible effects of the amendment, officials said last month, but the results of any review have not been released.

The White House statement on the spending bill, which is now on the House floor, also includes opposition to restriction on local funding for abortions, the ban on federal funding for needle exchange, and cuts to the District’s college tuition grant program.

If the House passes the budget bill as expected, its inclusion in any spending law would be subject to negotiation with Democrats, and Obama’s opposition could be helpful in that process. Del. Eleanor Holmes Norton (D-D.C.) called it “indispensable” in a Monday statement. But it is hardly a magic bullet: In a high-stakes 2011 budget negotiation, Obama famously traded away the District’s ability to spend locally raised tax funds on abortion in talks with House Speaker John A. Boehner (R-Ohio).